Field of the Invention
The present invention relates to a distribution enclosure for optical fibres in telecommunication networks and a manufacturing method for such an enclosure.
Background
In fibre-optic networks, a feeder cable leads a large number of optical fibres towards a geographical area in which a number of customers, e.g. households or enterprises, are located. In the vicinity of the customers, some of the optical fibres of the feeder cable are connected to other optical fibres, so-called drop fibres, which lead to individual customers. This connection of feeder cable fibres to drop fibres is often done by splices. At a splice, a bare feeder cable fibre is mechanically and optically coupled to a bare drop fibre. In order to protect splices against environmental impacts, splices are often arranged in distribution enclosures. These enclosures may, for example, have a base and a cover forming a housing, and a seal between base and cover to keep dust and water out. Besides protection of fibres and splices, such enclosures often also facilitate an orderly arrangement of the splices. In particular, some enclosures can accommodate a number of so-called splice trays, which provide locations for splices and space for storage of fibre overlength (“slack storage”) in a space-saving arrangement. Often, a number of such splice trays can be mounted, e.g. in a fixed or pivotable manner, on a tray holder, which itself is fixed to the inside of the housing.
In a distribution enclosure, normally only some fibres of the feeder cable will be spliced to drop fibres. The remaining feeder cable fibres, sometimes called “express fibres”, remain intact and unspliced. They are therefore not routed into splice trays. The distribution enclosure must, however, provide storage space for the overlength of those express fibres. For that purpose, many distribution enclosures comprise a separate slack fibre storage compartment, which can be used to store overlength of express fibres and of other fibres or cables.
An enclosure, or closure, of generally such a type is described in the international patent application WO 94/24599. That closure includes a frame having a partition wall to define front and rear access areas for the enclosure. The frame carries one or more splice trays on a first surface portion making the splices accessible from the front or first access area. A slack storage compartment is provided on the second surface portion.
The U.S. Pat. No. 5,553,186 discloses a fibre optic dome closure which has a body with a closed end and an open end, a tubular base releasably secured to the open end, a strain relief member attached to the base, having cable ports therein, and several fiber optic storage trays supported in the body. The trays include a transition tray which receives excess fiber slack, and two or more splice trays hingedly attached at a common end to either the transition tray or to another splice tray.
A further fibre optic splice closure is described in the international patent application WO 03/040774 A2. The closure comprises a tray holder, secured to a bottom cover of the closure, and a substantially planar splice tray. The closure is configured to store slack fibers around the perimeter of the tray holder and the splice trays.
In traditional fibre optic enclosures, the housing, the tray holder and/or the slack fibre storage compartment are separate parts which are connected to each other during assembly of the enclosure. Separate parts require separate manufacturing steps and separate tools for the manufacturing process, e.g. separate plastic molds. Assembling the separate parts to form the enclosure requires extra time. The present invention aims at addressing these problems.